A Drug Enforcement Administration agent intimately involved in the Silk Road investigation admitted on Wednesday he secretly accepted bitcoins from the underground website’s operator and illegally took other funds.

Carl Mark Force IV, who was a DEA agent for 15 years, pleaded guilty to money laundering, obstruction of justice and extortion under color of official right, according to the plea agreement, filed in U.S. District Court for the Northern District of California.

Force, who was based in Baltimore, was part of a multi-agency task force investigating the Silk Road, an underground marketplace for goods such as drugs and fake ID documents. It was shut down in October 2013.

Its operator, Ross Ulbricht, was sentenced to two concurrent life sentences and 40 years of additional terms. Ulbricht plans to appeal based in part on the actions of Force and a Secret Service investigator, Shaun Bridges.

Force was accused of having the DEA freeze the account of a Silk Road user and transferring the $297,000 into his own personal account rather than to the agency.

He also took two payments of bitcoins directly from Ulbricht, totaling about $148,000, in 2013. Using two online nicknames—French Maid and Nob—he convinced Ulbricht he had inside information about federal investigations into the Silk Road.

Bridges, who was charged with money laundering and obstruction of justice, took more than $800,000 worth of bitcoins from Silk Road using a hijacked administrator account, the DOJ said. He also reached a plea agreement with prosecutors.

The involvement of two corrupt federal agents in the Silk Road investigation has given Ulbricht’s attorney, Joshua Dratel, fuel for an appeal. He has claimed the investigation was flawed and that the government concealed evidence necessary for his client’s defense.

Although Dratel knew of the investigation of Force during the trial, he was not allowed to introduce facts about it into evidence. The involvement of Bridges was revealed in March, weeks after Ulbricht was convicted on Feb. 4.